1. Field of the Invention
The invention relates to a method for monitoring the functions of an elevator, in which method the functions of the elevator are observed continuously and at least changes occurring in the functions are registered and the events and their times of occurrence are stored in a memory associated with the elevator, and in which method the stored information about events and their times of occurrence is read from memory and presented on a display device associated with the elevator. The invention also relates to an apparatus for monitoring the traffic events of an elevator and displaying error conditions.
2. Description of the Related Art
The operation of an elevator consists of a series of chronologically distinct events. Using the elevator's call devices, elevator users give call signals, which are transmitted to the elevator control system. The elevator serves the calls as directed by the control system of the elevator or elevator group and sends control signals to the various regulating units of the elevator, such as the drive motor, door operating equipment and display units. As the elevator receives control commands and performs corresponding functions, the status and operation of the regulating units of the elevator are monitored by measuring their input and output signals. This monitoring is performed to maintain statistical information about the functions of the elevator, and the data collected and stored is utilized in elevator maintenance and in the planning of better elevator drives. The stored sequences of events are also utilized when examining abnormal behavior of the elevator and working out the causes that resulted in such behavior.
In a prior-art solution, traffic events and elevator control commands are stored in a memory comprised in the control unit of the elevator. The control unit is provided with a real-time monitoring display, by means of which the traffic events of the elevator can be monitored. This solution also has a playback function which makes it possible to track down the status of an elevator or elevator group at a given instant and to restore the display image corresponding to that instant. The display corresponding to the status at the instant in question shows e.g. the positions of the elevator cars, the modes and calls of the elevator group and the elevators. The playback function allows subsequent animation of traffic situations. When the relevant instant, e.g. the time of occurrence of a malfunction, is known, the causes of the failure may be inferred from the information relating to that instant and from the traffic history preceding it.
This prior-art solution involves numerous problems that make it difficult to apply in practice to unravel a failure. The monitor display shows only traffic events and the time, which changes in accordance with the recording. A serviceman or other user of the apparatus therefore has to record the times of occurrence of the error events manually for the time of the playback. During playback, the user has to observe a large number of simultaneous traffic events and also to observe and compare the time running on the display with the manually recorded time of occurrence of the malfunction. Several error messages may appear almost simultaneously, so it is difficult to remember them all. Locating a given point in the recording accurately and quickly is difficult and may be frustrating if the search has to be repeated several times e.g. when certain details are to be checked against previous traffic history. There is no easy access to information about corresponding earlier error messages, which could help establish the causes of a failure on the basis of event history. Especially in cases where a failure is associated with certain clearly recognizable foretokens, this information is of great importance for the identification of the fault.
Previously known is also the possibility of viewing error histories. However, this only provides access to exact times of occurrence of errors, and only information relating to error events can be displayed.
The object of the present invention is to provide a method and apparatus to achieve a new solution for monitoring elevator events without the drawbacks mentioned above.